In U.S. Pat. No. 3,744,068, for example, a well-known type of adjustable bed frame is disclosed. A problem has long existed in the art because frame members of this type have not provided positive interlocking engagement between sliding elements which make up the cross or transverse frame members without the need of a large number of fasteners. In addition, the assembling and disassembling of the elements is time consuming and complicated because if, by chance, the width has been assembled too narrow or too wide for the particular box spring and mattress, the box spring and mattress should be completely removed before any readjustment could be made.